<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
     body {
      margin: 0;
      height: 100vh;
      display: flex;
      align-items: center;
      justify-content: center;
      background-color: skyblue;
    }

    .window {
      font-size: 8px;
      position: relative;
      width: 25em;
      height: 35em;
      background-color: gainsboro;
      border-radius: 5em;
      box-shadow: 
        inset 0 0 8em hsla(0, 0%, 0%, 0.2),
        0 0 0 0.4em gray,
        0 0 0 4em whitesmoke,
        0 0 0 0.4em gray,
        0 2em 4em 4em hsla(0, 0%, 0%, 0.1);
      overflow: hidden;
    }

    .window .curtain {
      position: absolute;
      top: -20%;
      width: inherit;
      height: 30%;
      background-color: whitesmoke;
      border-radius: 5em;
      box-shadow: 
        0 0 0 0.4em gray,
        0 0 3em hsla(0, 0%, 0%, 0.4);
      z-index: 1;
    }

    .window .curtain::before {
      content: "";
      position: absolute;
      width: 40%;
      height: 0.8em;
      background-color: gray;
      border-radius: 0.4em;
      left: calc((100% - 40%) / 2);
      bottom: 1.6em;
    }

    .window .outside {
      width: 20em;
      height: 30em;
      background-color: deepskyblue;
      position: relative;
      left: calc((100% - 20em) / 2);
      top: calc((100% - 30em) / 2);
      border-radius: 7em;
      box-sizing: border-box;
      border: 0.4em solid gray;
      overflow: hidden;
    }

    .outside .cloud {
      position: absolute;
      width: 11em;
      height: 4em;
      color: white;
      background-color: currentColor;
      top: 20%;
      border-radius: 4em;
    }

    .outside .cloud::after,
    .outside .cloud::before {
      content: "";
      position: absolute;
      width: 4em;
      height: 4em;
      background-color: currentColor;
      border-radius: 50%;
    }

    .outside .cloud::after {
      top: -1em;
      left: 5em;
    }

    .outside .cloud::before {
      top: -2em;
      left: 2em;
    }

    .outside .cloud,
    .outside .cloud::after,
    .outside .cloud::before {
      box-shadow: 
        14em 6em,
        6em 15em;
    }
  </style>
</head>
<body>
  <h1 style="text-align: center; color: white">飞机舷窗</h1>
  <figure class="window">
    <div class="curtain"></div>
    <div class="outside">
      <span class="cloud"></span>
    </div>
  </figure>
</body>
</html>